Enlarging Time Machine space

[PeterJP]

Hi,

I have an MPB13 with a 256GB SSD that I'm backing up to an external drive and to a Linux server using Time Machine. The server used to have just a bit more space than the SSD, around 270GB.

I just increased that space to 480GB. I wiped the old backup (still have that historical data on the external hard drive anyway) and started a new backup. I interrupted it immediately after the start to increase the band size (see this article). Then I restarted the backup. It finished successfully, but Time Machine showed a backup disk size of around 270GB. That backup disk had around 59.9GB free.

I opened the sparsebundle in Disk Utility and increased the size to 480GB. Disk Utility did this and it shows that the Time Machine partition has more than half of the space free. However, Time Machine now shows 59.9GB of 480GB available. So it's taken the free space and kept it.

I've tried plenty of things: using hdiutil to change the sparsebundle size, deleting the whole thing and starting again, nothing helps. I've reconfigured the Linux server to make sure that everything is correct. But Time Machine always starts out with the same size as the disk used to be before the resize. And if I resize it manually, the free space stays identical, despite the fact that the disk space has gone up.

Any idea?

Peter.

 

[Weaselboy]

Normally you would not do anything to expand the size of the sparse bundle image, since you don't need to. It will expand on its own as more data is added to it.

 

[PeterJP]

Well, in all my previous cases, the sparsebundle size was initially set to the size of the disk. So Time Machine would report: X GB of Y GB available. Y would be the size of the disk. X is then Y - (disk space currently in use).

In my new situation, I have a 1.4TB drive available and 225GB used on disk. When I do my first backup to the 1.4TB drive, Time Machine reports that I have 45GB available of 270GB. If I resize the sparsebundle myself to 480GB, the Disk Utility reports 255GB available, 225GB in use by "other". But Time Machine reports 45GB available of 480GB.

BTW, I want to use the remaining 920GB to backup another Mac, but that's another story. I'd first like to understand this incorrect size display.

Thanks!

 

[DeltaMac]

hmm
As Weaselboy said, the Time Machine backup expands to the space that it needs for a backup, whenever it needs to, also assuming that more space is, in fact, available. If space is NOT available to expand, then Time Machine will delete the oldest backups so enough space is available.
Bottom line: You should never need to increase the sparsebundle space manually. Time Machine does that automatically.

I would suggest that if you are using the 1.4TB drive to back up two different Macs, you should format the backup drive with two partitions, and set Time Machine on each Mac to use one of those partitions. And - let Time Machine take care of itself. Beyond giving it enough space (2x to 2.5x the size of the volume that you need to keep backed up is a good rule-of-thumb estimate for the space that Time Machine can use), you really don't need to do housekeeping on a Time Machine backup. It's supposed to be that simple

 

[PeterJP]

Hmmm, I really have to look at my setup then. When I tried to back up my other mac (a Hackintosh, actually, restored from a backup of my MBP13), it refused to do it because of lack of space. There's still 920GB entirely unclaimed. The only thing on that partition is 480 for the MPB TM backup (not all allocated yet). I've reformatted the partition, I've redone the entire netatalk config, and so on, but both my MBP and my Hackintosh are confused by it.

 

[DeltaMac]

How large is the hard drive or drives on the hackintosh? If it is a 1TB drive, for example, I think that TM will not support a backup when only 920GB maximum is available on your backup partition. You would need a backup with enough space to back up the potential full drive, if needed.

 

[Weaselboy]

Hmmm, I really have to look at my setup then. When I tried to back up my other mac (a Hackintosh, actually, restored from a backup of my MBP13), it refused to do it because of lack of space. There's still 920GB entirely unclaimed. The only thing on that partition is 480 for the MPB TM backup (not all allocated yet). I've reformatted the partition, I've redone the entire netatalk config, and so on, but both my MBP and my Hackintosh are confused by it.

My thought is all the messing around you have done with the sparse bundle may have borked it so that it no longer expands as it should. For example, you can make a disk image that is a set size and does not expand, and I'm wondering if that is what you have now.

How about if you copy the sparse bundle off to another drive. Then start a new networked backup and stop it after a couple minutes. Then open that new sparse bundle image and delete the Backups.backupdb file from it. Then move the Backups.backupdb file from inside the old sparse bundle to inside the newly created one. That should get you a properly configured sparse bundle with your existing backup in it.

 

[PeterJP]

1) My Hackintosh has a 500GB SSD, so 920GB is plenty. Same for the MBP13, it has 256GB and the foreseen TM space is 480GB.
2) The sparse bundle that I worked on was a fresh one. The only thing I did was to resize the bands, as mentioned above. After that, TM told me it had 270GB space, of which 45GB was available. And that was on the empty 1.4GB drive. That's why I started manually increasing the sparse bundle size: in all my previous experiences, TM immediately recognised the disk size correctly and it would show X GB free of Y, where Y was the full disk size. But it doesn't do that now.

Also, the articles I read about backing up a second Mac to a networked drive all say that the second Mac will just create a new sparse bundle. In my case, it seems to be trying to work inside the same sparse bundle. There's almost 1.2TB free on the drive, yet TM claims there's not enough space to back up about 250GB.

I'll see if I can try to make a new sparse bundle like you say, Weaselboy. Unfortunately, I don't have good hopes because that's how I made the current sparse bundle (empty partition, start TM, stop after a few minutes, resize bands, restart backup) and it's still giving me the wrong available space

 

[Weaselboy]

I'll see if I can try to make a new sparse bundle like you say, Weaselboy. Unfortunately, I don't have good hopes because that's how I made the current sparse bundle (empty partition, start TM, stop after a few minutes, resize bands, restart backup) and it's still giving me the wrong available space

I'm wondering if messing about trying to change that bands setting is what is breaking things for you? Can you try starting a fresh backup like I mentioned without the bands switch and see if that works okay.

 

[PeterJP]

I'll try that first. There are articles that claim band sizes can break time machine, but much of this information is about lion or yosemite. Thanks!

 

[PeterJP]

I'd like to come back to this issue because I found the problem and I think others may experience the same.

It turns out that, in one of my attempts to configure my server for 2 Time Machines, I limited my AFP volume size. So, my partition was 1.4TB. But in the afp.conf, I set the size of the exported AFP volume for Time Machine to 270GB as follows:

[TimeMachine]
path = /mnt/tmPart
time machine = yes
vol size limit = 270000

I decided to work with two AFP volumes: one for my MBP and another for my Hackintosh. So I made 2 subdirectories at the top level of my partition and exported both as a separate AFP volume. In afp.conf, it looks like this now:

[TMMBP]
path = /mnt/tmPart/MBP
time machine = yes
vol size limit = 480000
[TMHack]
path = /mnt/tmPart/Hack
time machine = yes
vol size limit = 960000

On the MPB, I selected the TMMBP volume to back up to. It shows up as 480GB size in Time Machine. I still have to reconfigure the Hackintosh.